From be52ac73d120b5bf27f13c41656c6cfe132c8c30 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 16 Jan 2018 09:53:09 +0100
Subject: [PATCH] re PR tree-optimization/83843 (wrong code at -O2)

	PR tree-optimization/83843
	* gimple-ssa-store-merging.c
	(imm_store_chain_info::output_merged_store): Handle bit_not_p on
	store_immediate_info for bswap/nop orig_stores.

	* gcc.dg/store_merging_18.c: New test.

From-SVN: r256727
---
 gcc/ChangeLog                           |  7 ++++
 gcc/gimple-ssa-store-merging.c          |  9 +++++
 gcc/testsuite/ChangeLog                 |  3 ++
 gcc/testsuite/gcc.dg/store_merging_18.c | 51 +++++++++++++++++++++++++
 4 files changed, 70 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/store_merging_18.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c4af56fc340..69ed57a5b50 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2018-01-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/83843
+	* gimple-ssa-store-merging.c
+	(imm_store_chain_info::output_merged_store): Handle bit_not_p on
+	store_immediate_info for bswap/nop orig_stores.
+
 2018-01-15  Andrew Waterman  <andrew@sifive.com>
 
 	* config/riscv/riscv.c (riscv_rtx_costs) <MULT>: Increase cost if
diff --git a/gcc/gimple-ssa-store-merging.c b/gcc/gimple-ssa-store-merging.c
index 9321177d761..92ddfb55543 100644
--- a/gcc/gimple-ssa-store-merging.c
+++ b/gcc/gimple-ssa-store-merging.c
@@ -3619,6 +3619,15 @@ imm_store_chain_info::output_merged_store (merged_store_group *group)
 		  gimple_seq_add_stmt_without_update (&seq, stmt);
 		  src = gimple_assign_lhs (stmt);
 		}
+	      inv_op = invert_op (split_store, 2, int_type, xor_mask);
+	      if (inv_op != NOP_EXPR)
+		{
+		  stmt = gimple_build_assign (make_ssa_name (int_type),
+					      inv_op, src, xor_mask);
+		  gimple_set_location (stmt, loc);
+		  gimple_seq_add_stmt_without_update (&seq, stmt);
+		  src = gimple_assign_lhs (stmt);
+		}
 	      break;
 	    default:
 	      src = ops[0];
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7bbeafafa34..506113a4e61 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2018-01-16  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/83843
+	* gcc.dg/store_merging_18.c: New test.
+
 	PR c++/83817
 	* g++.dg/cpp1y/pr83817.C: New test.
 
diff --git a/gcc/testsuite/gcc.dg/store_merging_18.c b/gcc/testsuite/gcc.dg/store_merging_18.c
new file mode 100644
index 00000000000..43de6ed3d5d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/store_merging_18.c
@@ -0,0 +1,51 @@
+/* PR tree-optimization/83843 */
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-store-merging" } */
+/* { dg-final { scan-tree-dump-times "Merging successful" 3 "store-merging" { target store_merge } } } */
+
+__attribute__((noipa)) void
+foo (unsigned char *buf, unsigned char *tab)
+{
+  unsigned v = tab[1] ^ (tab[0] << 8);
+  buf[0] = ~(v >> 8);
+  buf[1] = ~v;
+}
+
+__attribute__((noipa)) void
+bar (unsigned char *buf, unsigned char *tab)
+{
+  unsigned v = tab[1] ^ (tab[0] << 8);
+  buf[0] = (v >> 8);
+  buf[1] = ~v;
+}
+
+__attribute__((noipa)) void
+baz (unsigned char *buf, unsigned char *tab)
+{
+  unsigned v = tab[1] ^ (tab[0] << 8);
+  buf[0] = ~(v >> 8);
+  buf[1] = v;
+}
+
+int
+main ()
+{
+  volatile unsigned char l1 = 0;
+  volatile unsigned char l2 = 1;
+  unsigned char buf[2];
+  unsigned char tab[2] = { l1 + 1, l2 * 2 };
+  foo (buf, tab);
+  if (buf[0] != (unsigned char) ~1 || buf[1] != (unsigned char) ~2)
+    __builtin_abort ();
+  buf[0] = l1 + 7;
+  buf[1] = l2 * 8;
+  bar (buf, tab);
+  if (buf[0] != 1 || buf[1] != (unsigned char) ~2)
+    __builtin_abort ();
+  buf[0] = l1 + 9;
+  buf[1] = l2 * 10;
+  baz (buf, tab);
+  if (buf[0] != (unsigned char) ~1 || buf[1] != 2)
+    __builtin_abort ();
+  return 0;
+}